The present invention relates, in general, to an adjustable extension pole and, more particularly, to an improved locking mechanism for a telescopically adjustable extension pole.
There are numerous types of extension poles that can be used for painting or other applications, e.g., sweeping attachments, swimming pool cleaning nets, and which allow the user to adjust the overall length thereof. For example, such poles permit the attachment of a paint roller frame to the end thereof allowing the painter to paint walls and ceilings without the use of a ladder. Such poles typically utilize telescoping members for length adjustment purposes and some type of locking mechanism to interlock the telescoping members after the desired length of the pole has been attained. It has been found that these locking mechanisms usually have some type of inherent structural or operational disadvantages. For example, the adjustable extension pole disclosed in U.S. Pat. No. 5,220,707 (Newman, Sr., et al.) utilizes a locking mechanism comprising a Belleville-type washer arrangement which is connected to a pin which interlocks the outer telescoping sleeve within the inner telescoping sleeve. By depressing a push button operatively connected to the Belleville-type washer, the washer is deformed causing the pin to be withdrawn from the inner sleeve permitting the inner sleeve to be telescopically adjusted within the outer sleeve. Operationally, the aforementioned locking mechanism has some inherent disadvantages since, through use, the washer becomes fatigued causing the locking mechanism to malfunction. In addition, since a push button arrangement is used, paint can be easily entrapped under and around same affecting the xe2x80x9csnap-actionxe2x80x9d ability of the Belleville-type washer.
Another tube or sleeve locking mechanism is disclosed in U.S. Pat. No. 3,596,946 (Burton, et al.) which utilizes an unidirectional cam lock arrangement to interlock the sleeves after the desired length of the extension pole has been attained. In this case, the inner and outer sleeves must be properly aligned in order to operate the cam locking arrangement and the cam locking arrangement is susceptible to paint becoming entrapped therein causing the malfunction of same. Another tube or sleeve locking mechanism is disclosed in U.S. Pat. No. 4,662,771 (Roe, et al.). In this case, the locking mechanism is comprised of a relatively complex ball and detent arrangement received between machined sleeves connected to the extension pole. The ball and detent arrangement is relatively costly to produce, and the resulting locking mechanism is susceptible to paint being entrapped therein resulting in the possible malfunction of same. A further tube or sleeve locking mechanism is disclosed in U.S. Pat. No. 3,603,623 (Widman). This locking mechanism utilizes oppositely wound coil springs which surround the inner tubular sleeve. By changing the bias on the springs which can be accomplished by moving external knobs on the outer surface of the locking mechanism, the inner sleeve is released permitting its telescopic adjustment within the outer sleeve. In this case, the coil springs are subject to fatigue and breakage, and the locking mechanism is susceptible to paint being entrapped therein due to its use of external knobs to change the bias on the springs within same. Lastly, U.S. Pat. No. 5,288,161 (Graves, et al.) discloses a locking mechanism which interlocks the end of an extension pole to the end of a paint roller frame. In this case, the extension pole is not telescopically adjustable, however, the locking mechanism permits the attachment of the pole, which can be any length, to the end of the paint roller frame. The locking mechanism disclosed in this patent is comprised of a lever arrangement which is external to the end of the pole, and thus, is very susceptible to paint being entrapped therein causing the locking mechanism to become difficult to operate or inoperable.
Because of the fore going inherent disadvantages associated with presently available extension poles, it has become desirable to develop an extension pole locking mechanism that is durable, is easy to produce, assemble and operate and which is not susceptible to paint being entrapped therein.
The present invention solves the problems associated with prior art extension poles and other problems by providing an extension pole locking mechanism which comprises a minimum number of components, is less susceptible to paint being entrapped therein, and is extremely simple to produce and operate. The locking mechanism of the present invention comprises an outer tubular sleeve, an inner tubular sleeve received within the outer tubular sleeve and a collar assembly attached to the outer tubular sleeve. The collar assembly comprises a collar member attached to the outer tubular sleeve and a locking trigger mechanism which is received over the collar member and includes a bottom trigger member and a top trigger member having a locking pin therein. The top trigger member has a circular configuration and grippingly engages the collar member. The bottom trigger member has a U-shaped configuration and interlocks with the top trigger member. Because of the U-shaped configuration of the bottom trigger member, when the top and bottom trigger members are interlocked, a gap is created between the inner surface of the bottom trigger member and the collar member. By depressing the bottom trigger member, the gap between the bottom trigger member and the collar member closes causing the top trigger member to move laterally outwardly retracting the locking pin from the inner tubular sleeve permitting the length of the extension pole to be adjusted. After the desired length of the pole has been attained, if pressure is released on the bottom trigger member, the top trigger member will move laterally inwardly causing the locking pin therein to be received in an aperture in the inner tubular sleeve locking the inner tubular sleeve within the outer tubular sleeve at the approximate desired length of the extension pole.
Accordingly, it is an object of the present invention to provide an extension pole locking mechanism which utilizes a minimum number of components.
Another object of the present invention is to provide an extension pole locking mechanism which is less susceptible to paint being entrapped therein.
A still another object of the present invention is to provide an extension pole locking mechanism that is durable.
A further object of the present invention is to provide an extension pole locking mechanism that is relatively inexpensive to produce and is easy to assemble.
A still further object of the present invention is to provide an extension pole locking mechanism that can be easily replaced, if necessary.